Background- Neoplastic diseases are one of the main factors that threaten the life span of pet birds. Osteoma and osteosarcoma are considered as the most prevalent of neoplasms in the skeletal system, which were reported in several species of the birds.Case Description- This paper describes gross and histopathological features of telangiectatic osteosarcoma in an adult male budgerigar (Melopsittacus undulatus) with weakness, general depression and weight loss. Clinical Findings- At necropsy, a

more »

... irm mass with approximately one cm in size and brown color involved the tibiotarsus. Pathology examination of the mass indicated bloody cystic lesions accompanied by occasional spicules of osteoid between pleomorphic mesenchymal cells, which it was found minimal. Clinical Relevance- Telangiectatic osteosarcoma should be differentiated from either hemangiosarcoma or aneurysmal bone cyst. This is the first report of osteosarcoma in the budgerigar.